A Large-Scale Genome-Wide Study of Gene-Sleep Duration Interactions for Blood Pressure in 811,405 Individuals from Diverse Populations.

Although both short and long sleep duration are associated with elevated hypertension risk, our understanding of their interplay with biological pathways governing blood pressure remains limited. To address this, we carried out genome-wide cross-population gene-by-short-sleep and long-sleep duration interaction analyses for three blood pressure traits (systolic, diastolic, and pulse pressure) in 811,405 individuals from diverse population groups. We discover 22 novel gene-sleep duration interaction loci for blood pressure, mapped to genes involved in neurological, thyroidal, bone metabolism, and hematopoietic pathways. Non-overlap between short sleep (12) and long sleep (10) interactions underscores the plausibility of distinct influences of both sleep duration extremes in cardiovascular health. With several of our loci reflecting specificity towards population background or sex, our discovery sheds light on the importance of embracing granularity when addressing heterogeneity entangled in gene-environment interactions, and in therapeutic design approaches for blood pressure management.

Digital Connectedness in the Jackson Heart Study: Cross-sectional Study.

BACKGROUND: Although new approaches for data collection, such as mobile technology and teleresearch, have demonstrated new opportunities for the conduct of more timely and less costly surveys in community-based studies, literature on the feasibility of conducing cardiovascular disease research using mobile health (mHealth) platforms among middle-aged and older African Americans has been limited. OBJECTIVE: The purpose of this study was to contribute to the knowledge regarding the penetrance of internet and mobile technologies, such as cellphones or smartphones in existing large cohort studies of cardiovascular disease. METHODS: A digital connectedness survey was conducted in the Jackson Heart Study (JHS), a Mississippi-based African American cohort study, as part of the annual follow-up calls with participants from July 2017 to February 2019. RESULTS: Of the 4024 participants contacted, 2564 (63.7%) completed the survey. Among survey respondents, 2262 (88.2%) reported use of internet or cellphone, and 1593 (62.1%) had a smartphone. Compared to nonusers (n=302), internet or cellphone users (n=2262) were younger (mean age 80.1, SD 8.0 vs 68.2, SD 11.3 years), more likely to be affluent (n=778, 40.1% vs n=39, 15.4%), and had greater than high school education (n=1636, 72.5% vs n=85, 28.1%). Internet or cellphone users were less likely to have cardiovascular disease history compared to nonusers (136/2262, 6.6% vs 41/302, 15.8%). The prevalence of current smoking and average BMI were similar between internet or cellphone users and nonusers. Among internet or cellphone users, 1316 (58.3%) reported use of email, 504 (22.3%) reported use of apps to track or manage health, and 1269 (56.1%) expressed interest in using JHS-developed apps. CONCLUSIONS: Our findings suggest that it is feasible to use mHealth technologies to collect survey data among African Americans already enrolled in a longitudinal study. Our findings also highlight the need for more efforts to reduce the age and education divide in access and use of internet and smartphones for tracking health and research in African American communities.

Obesity and overall mortality: findings from the Jackson Heart Study.

BACKGROUND: Overall mortality has been reported to be lower among individuals classified as overweight/obese when compared with their normal weight counterparts ("obesity paradox") when obesity classification is based on the body mass index (BMI). One possible reason for this apparent paradox is that BMI is not a reliable measure of obesity-related risk as it does not differentiate fat mass from lean muscle mass or fat mass phenotypes. Waist circumference (WC), as a measure of central adiposity, may be a better indicator of obesity-related risk. We examined the association of overall mortality with BMI and with WC measures, including WC, waist-to-height ratio (WHtR) and waist-to-hip ratio (WHR). METHODS: Data from 3976 African American participants (551 deaths) in the Jackson Heart Study (JHS) were analyzed. Cox regression models were used to perform survival analysis. Obesity measures were analyzed as dichotomous (obese/non-obese) and continuous variables. Baseline covariates included age, sex and smoking status. RESULTS: Comparing obese to non-obese participants, adjusted hazard ratios (95% CI) for overall mortality were 1.14 (0.96, 1.35), 1.30 (1.07, 1.59), 1.02 (0.73, 1.41) and 1.45 (1.18, 1.79) when using BMI, WC, WHtR and WHR, respectively. For BMI, WC and WHtR, a J-shaped relationship was observed with overall mortality. For WHR, a monotonic increasing relationship was observed with overall mortality. CONCLUSIONS: In the JHS, we found that obesity as defined by WC and WHR was associated with an increased risk of overall and CVD mortality, while obesity defined by BMI was associated only with an increased risk of CVD mortality. WHR was the only obesity measure that showed a monotonic increasing relationship with overall and CVD mortality.